$\cos B=0,6$
$\to \sin B=\sqrt{1-0,6^2}=0,8$
$\to \tan B=\dfrac{\sin B}{\cos B}=\dfrac{4}{3}$
$\to \cot B=\dfrac{1}{\tan B}=0,75$
Ta có: $\Delta ABC$ vuông tại $A$ nên $\widehat{B}+\widehat{C}=90^o$
Vậy:
$\sin C=\cos B=0,6$
$\cos C=\sin B=0,8$
$\tan C=\cot B=0,75$
$\cot C=\tan B=\dfrac{4}{3}$
Xét $ΔABC$ vuông tại $A$
Do $\widehat{B},\widehat{C}$ phụ nhau nên $sinC=cosB=0,6$
Ta có $sin^2C+cos^2C=1$
$⇔cos^2C=1-sin^2C$
$⇔cos^2C=1-0,6^2$
$⇔cos^2C=\dfrac{16}{25}$
Do $ΔABC$ vuông nên $\widehat{C}$ là góc nhọn nên $cosC>0$
$⇔cosC=\dfrac{4}{5}$
$tanC=\dfrac{sinC}{cosC}=\dfrac{3}{4}$
$cotC=\dfrac{1}{tanC}=\dfrac{4}{3}$
TASK 3:IN/ON/AT 1. School starts September. 2. We will talk lunchtime. 3. She visited Japan 7th July. 4. 5. The shop opens nine. 6. 7. My father was born 1985. 8. 9. We sang a song my birthday. 10. 11. Pamela will come back night. 12. 13. We have tea the afternoon. 14. 15. I will see you Monday. 16. 17. There are flowers spring. 18. 19. 20. TASK 4: 1. We danced tango the 1920s. 2. The bus left five past ten. 3. We go to the beach summer 4. Where were you 31st July? 5. They will go away Easter. 6. I drink coffee the morning. 7. We saw the moon midnight. 8. They arrived Friday evening. 9. He is busy the moment. 1. I'll see you next week. 2. He was born 1991. 3. Did you see her today. 4. It starts tomorrow. 5. It was sunny my birthday. 6. It will be ready eight months. 7. What's on the TV midnight. 8. The factory closed June. 9. the winter, it usually snows. 10. Friday, she spoke to me. 11. What are you doing the weekend. 12. I'll see you a moment. 13. The anniversary is May 10th. 14. Where did you go last summer. 15. The movie starts 20 minutes. 16. the moment, I'm busy. 17. They were very popular the 1980s. 18. My appointment is Thursday morning. 19. We had the meeting last week. 20. Are you staying at home Christmas Day. 21. I have to speak to the boss lunchtime. 22. 8 o'clock, I must leave HÃY GIÚP MÌNH
III.Circle the letter A, B, C, or D to indicate the correct answer to each of the following questions. 4. Our school football team____________ the match with Nguyen Du school last Saturday. A. wins B. won C. win D. to win 5. ____________ draw on the walls and tables, please! A. Do B. Don't C. Should D. Shouldn't 6. I know I should take exercise, but I____________ do. A. ever B. often C. never D. always 7. We were very upset when our favorite team____________ even one goal. A. played B. didn’t take C. made D. didn’t score 8. Badminton requires only a net, shuttlecock or____________. A. ball B. ski C. a racket D. goggles 9. When you go to the zoo, don't____________ the animals. A. look B. see C. tease D. watch 10. "I'd like to watch motor racing because it is very____________." A. frightening B. exciting C. excited D. boring 11. Team sports are sometimes called____________ sports. A. compete B. competition C. competitor D. competitive 12. Pele is widely____________ as the best football player all of time. A. regarded B. became C. liked D. thought IV.Circle the letter A, B, C, or D to indicate the underlined part that needs correction in each of the following questions. 13. Did your uncle took you to watch the football match last week? A. Did B. took C. to watch D. football match 14. Skiing, skating and karate is my favorite sports. A. Skiing B. and C. is D. sports
Một cửa hàng trong hai ngày bán đc 620 kg gạo Hỏi trong 7ngày cửa hàng bán đc bao nhiêu kg gạo (biết rằng mỗi ngày bán đc là như nhau)
Làm giúp em 1 bài trong đây thôi ạ, em cảm ơn em đang cần gấp, chi tiết và dễ hiểu ạ
Vẽ đậu mầm : vui buồn mệt mỏi tức giận lười biếng
vẽ mầm cho mink nhé, trên app ibis nha mn ^^
Giúp mình ko làm tắt đầy đủ và chỉ có 1 câu tìm x
an toàn thực phẩm là gì? cho bt các cách phòng tránh nhiễm trung nhiễm độc
(X+1)(x^2-x+1) (X-2)(x^2+2x+4 ) (X-3)(x^2+3x+9)
Viết bài văn tả một buổi sáng đẹp trời ở làng quê em. NHANH GIÚP MÌNH NHÁAAAA
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